Nowadays it is known to manufacture shoes, such as for example ski boots, which usually comprise a shell and at least one quarter, made of plastics, with which soft innerboots are associated to increase the user's comfort.
Equally, it is known to manufacture sports shoes, such as for instance for trekking or climbing, which are usually constituted by a sole with which a shell or upper is associated; a lining or a padding or a sock is inserted or stitched inside the shell or upper.
These known solutions have some drawbacks: first of all assemblying the upper and the lining with basically manual operations, such as stitching, gluing, or welding, entails long production times which consequently lead to high production costs.
Furthermore, the use of plastics makes the shell or upper to be considerably rigid. Accordingly, while on one hand the technical features of the shoe can be improved, on the other hand the user's comfort and foot transpiration are impaired.
Furthermore, the use of stitches makes the shoe permeable to water.
In order to overcome these drawbacks it is known for example to manufacture overlap-style shells for ski boots: however, this entails another problem linked to the waterproofing of the shell and to the thermal insulation thereof.